We present evidence of the rates of late Quaternary tectonic uplift that have affected parts of central Greece during this period of active extension and basin formation. Dual lines of evidence indicate upper Pleistocene to Holocene uplift rates of the order of 0.3 mm yr -1 for the Corinth and Megara basins. First, U-series disequilibrium ages of Acropora sp. corals from uplifted marine sediments are used to derive minimum average rates of vertical displacement since deposition. Second, the geometries of cyclical transgressive sequences and of erosional terraces are consistent with the radiometric evidence and the known history of late Quaternary sea level fluctuations. Two types of uplift are distinguished on the basis of structural relationships: (1) fault block rotation about a horizontal axis (tilting) in response to footwall uplift on the active normal fault bounding the Alkyonides Gulf and (2) a more regional uplift which affects the Corinth Basin and Peloponnesos to the south. The results of U-series dating are discussed in the light of initial 234U/238U activity ratios, derived from the coral samples, which are higher than for average marine waters (1. 17-1.31 compared to 1.14). These values may be related to a variable freshwater input to the structurally confined Gulf of Corinth or, alternatively, they may reflect a previously higher global 234U/238U activity ratio in marine waters, or post-mortem enrichment in 234U, although the mechanism of the latter is not yet understood. Aegean has been an area of active crustal extension[McKenzie, 1978; Le Pichon and Angelier, 1981; Jackson et al., 1982a, 1982b]. Characteristic halfgraben and asymmetric graben basins are developing in response to the rapid extensional strain rates which are accompanied by intense seismicity [Jackson and McKenzie, 1988]. Very high rates of three-dimensional rotations are occurring between fault-bounded blocks [Jackson and McKenzie, 1988; Billiris et al., 1991].

Geophysical, structural, geochronological and geomorphological data indicate that the Psatha, East Alkyonides, Skinos and Pisia faults are Holocene-active structures whereas the status of the West Alkyonides, Strava, Perachora and Loutraki faults is less certain. We see no evidence for significant lateral surface fault growth. New data for late Pleistocene footwall uplift of the Psatha fault are comparable with previously estimated Holocene rates. Pre-Holocene stratigraphic sequences in the Alkyonides Gulf allow calculation of vertical displacement on the Skinos fault of 1.42–1.60 km over a period of >0.6 Ma. Previous palaeoseismological studies indicate comparable displacement rates extrapolated to 0.61–2.20 Ma, whereas extrapolation of previous geodetic data indicate a range of 0.17–0.46 Ma. The latter is too short given the evidence of the stratigraphic record, signifying either that these data may not be representative of longer-term rates, or that significant deformation has taken place elsewhere, for example, on offshore antithetic faults. A case is established for uniform late Quaternary (post-MIS 7) uplift of the Perachora peninsula at rates of c. 0.2–0.3 mm a–1. The lack of regional tilting over Perachora–Corinth–Isthmia is in marked contrast to the situation in the Alkyonides–Megara basins to the east

S U M M A R YIn 1994, three shallow earthquakes of M w ∼ 6 occurred close together on blind thrusts near Sefidabeh in eastern Iran. In an earlier study of the teleseismic waveforms, the geomorphology and the faulting in the epicentral region, it was suggested that these earthquakes were associated with the growth of a ridge above a blind thrust fault system, whose activity could be detected by its effect on the surface drainage. In this study we present a SAR interferogram that precisely determines the location and amount of coseismic surface displacements, showing that the earthquakes in the Sefidabeh sequence probably occurred on en-echelon fault segments associated with three stepping ridges. We also present U/Th dates of ∼100 ka for lake deposits uplifted by the growing ridge. From the cumulative, dated uplift and knowledge of the surface displacements due to an earthquake sequence, we estimate that ∼120 such events have occurred in the past 100 ka, with an average recurrence interval of 830 yr, and an average convergence rate of 1.5 mm yr −1 on the Sefidabeh thrust; each estimate has an uncertainty of a factor of two, either way. We argue that the Sefidabeh fault originally formed by coalescence of many small fault segments, and has grown in length at about 2 cm yr −1 in the past 100 ka. Though the coseismic surface deformation observed in the SAR interferogram closely resembles folding, the overall topography does not, because of inherited topography associated with earlier geological deformation. In spite of this, the activity of the buried thrust fault can easily be detected by its effect on the surface drainage: a significant lesson when interpreting landscapes that are not entirely due to the present-day deformation.

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New evidence for uplift of the southern margin to the Corinth rift, one of the world's most rapidly extending continental regions, defines an area of uniform uplift separating a more rapidly uplifting western rift flank from a slowly backtilting eastern flank. This major tectonic boundary coincides with geophysical evidence for a junction between flat underlying subducted oceanic plate and steep subduction. We propose that trench rollback by the Anatolian plate over the subducting African plate has led to differential uplift and possible migration of active faulting at the southern rift margin in the last few million years.

A method for the isotope analysis of fluid inclusion water in speleothem calcite is presented. The technique is based on a commercially available continuous-flow pyrolysis furnace (ThermoFinnigan TC-EA). The main adaptation made to the standard TC-EA configuration is the addition of a crusher and cold trap unit, which is connected to the carrier gas inlet at the top of the TC-EA reactor tube. A series of tests conducted with this device shows that: (1) standard waters, injected in the crusher, and passed through a cryogenic trapping routine, yield accurate delta(2)H values; (2) crushed cubes of speleothem calcite from two Peruvian caves with rather dissimilar seepage water delta(2)H values yield fluid inclusion delta(2)H values in good accordance with these drip waters. The clear advantage of this continuous-flow technique for fluid inclusion isotope analysis is that it is relatively quick compared with other techniques. Since the conditions of water sample introduction into the TC-EA are identical for delta(2)H and delta(18)O analysis, we expect that only limited adaptations to the extraction procedure are required to provide delta(18)O analysis of fluid inclusion samples with the same device.

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